When hosts use a non-optimal or defunct route to a particular destination, an ICMP redirect packet is used by routers to inform the hosts what the correct route
should be. If an attacker is able to forge ICMP redirect packets, he or she can alter the routing tables on the host and possibly subvert the
security of the host by causing traffic to flow via a path you didn't intend. It's strongly recommended to disable ICMP Redirect Acceptance to
protect your server from this hole.